The present invention relates to a facility in a multi-system complex in which one software subsystem has the remote capability for interdicting or fencing I/O and messaging operations of another software subsystem.
A facility provides a program interface for the control of fencing operations. In particular, fencing commands manipulate the state of an authorization vector or CPC-isolation indicator at a remote CPC, and, in some cases, initiate a terminating function at that CPC. The terminating function scans all active I/O and message operations, terminating the appropriate operations as determined by the new state of the authorization vector or isolation indicator. Thereafter, the initiation of new I/O and message operations is regulated by the new state of the authorization vector or isolation indicator.